1. Field of the Invention
The present invention generally relates to controlling the release of a volatile substance, more particularly, to controlling the release of a predetermined amount of a volatile substance of fluid and isolating the container of the volatile substance from the outside environment.
2. Background Art
Prior art methods for delivering volatile substances from a container, for example a volatile substance such as a liquid, make use of absorbent material such as wicks. For example, one end of a wick is placed in a fluid to be dispensed, while the other end is exposed to the atmosphere. Capillary action will force liquid through the wick and to the exposed end of the wick. Once at the exposed end of the wick the liquid evaporates off of the end of the wick and into the surrounding atmosphere.
Other prior art fluid delivery systems have relied upon various types of gravity driven mechanisms, allowing fluids to diffuse through a membrane under the force of gravity. For instance, Zembrodt, U.S. Pat. No. 4,948,047 shows a container for holding a liquid reservoir which is in contact with a membrane positioned in the bottom of the container. Under the force of gravity, the liquid diffuses through the membrane and volatilizes into the surrounding atmosphere from the exposed surface of the membrane. Likewise, Munteanu, U.S. Pat. No. 4,917,301, discloses a similar container for housing a liquid, with a membrane in the bottom of the container. Gravity again forces the liquid to diffuse through the membrane, from where it then evaporates into the surrounding atmosphere. Joshi et al. also describes gravity based devices in U.S. Pat. Nos. 5,932,204, 6,109,539 and 6,419,163 B1.
Although these and other conventional controlled delivery systems have worked well they have failed to provide for both the controlled fixed amount of fluid to be released while isolating the rest of the fluid under large temperature swings or pressure swings occurring in some applications such as automobiles or airplanes and other temperature and pressure swing environments. Accordingly, such prior art devices have traditionally failed to isolate the volatile fluids from emanating under such high temperature or pressure swings, which, in turn, result in an excessive and rapid volatilization of fluids at a faster rate when no one is occupying the particular environment.
Furthermore such devices have failed to provide a means for a user to selectively dispense only a fixed amount of fluid on the emanator and isolate the rest of fluid in the container from exposure to the atmosphere when the volatile substance needs to be protected from coming into contact with the atmosphere.